2nd Gen Non-Engine/Transmission hard brake pedal

[runningbird]

we are having a problem with our brake pedal becoming hard at times, when this happens we have very little braking. I have recently put on a pac exhaust brake. I have double checked all the fittings and vacuum hoses and they seem fine. also when the pedal is hard the exhaust brake does not work,so I think I'm loosing vacuum. I do have a vacuum gauge at home, can any one tell me what kind of reading I should be looking for? also I checked the power steering fluid and it also seems ok.



any thanks for any help it was a pretty scary drive to work this a. m.

oh bye the way this is on our 94 2wheel drive 5 speed truck

 

[B.G. Smith]

Since the e-brake is acting up too, it is probably loss of vacuum. Could be a leak or the vac. pump may be goiong bad. Perfect vacuum would be 29. 8 in. hg at sea level. The pump should pull at least 25 in. bg